.left {
  width: 300px;
  height: 100%; /* 跟随父容器高度，替代固定500px */
 background-color: rgba(250, 247, 247, 0.5);
  position: relative;
  border-radius: 12px 0 0 12px; /* 仅左侧圆角，与整体容器配合 */
  box-shadow: 2px 0 8px rgba(0, 0, 0, 0.03);
  padding-top: 20px;
  box-sizing: border-box;
  transition: box-shadow 0.3s ease;
}

.left:hover {
  box-shadow: 2px 0 16px rgba(0, 0, 0, 0.06);
}

/* 左侧标题 */
.leftTitle {
  font-size: 16px;
  font-weight: 500;
  color: #333;
  text-align: center;
  margin-bottom: 30px;
  padding-bottom: 8px;
  border-bottom: 1px solid #f0e6d6;
}

/* 左侧按钮（新建会话） */
.leftTop {
  width: 120px;
  height: 42px;
  position: absolute;
  top: 80px;
  left: 50%;
  transform: translateX(-50%);
  background-color:  #1e88e5;
  color: #fff;
  border: none;
  border-radius: 24px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 0 16px;
  box-shadow: 0 2px 8px  #1e88e5(255, 122, 69, 0.3);
  transition: all 0.2s ease;
  outline: none;
}

/* 按钮加号图标 */
.leftTop .iconPlus::before {
  content: "+";
  font-size: 16px;
  font-weight: bold;
}

/* 按钮交互效果 */
.leftTop:hover {
  background-color: white;
  color:  #1e88e5;
  box-shadow: 0 4px 12px  #1e88e5(255, 122, 69, 0.4);
  transform: translateX(-50%) translateY(-2px);
}

.leftTop:active {
  transform: translateX(-50%) scale(0.96);
  box-shadow: 0 1px 4px rgba(255, 122, 69, 0.2);
}

.leftTop:disabled {
  background-color:  #1e88e5;
  cursor: not-allowed;
  box-shadow: none;
  transform: translateX(-50%);
}

/* 左侧响应式适配 */
@media (max-width: 768px) {
  .mainbody {
    width: 100%;
    height: 100vh;
    margin-top: 0;
    border-radius: 0;
  }
  
  .left {
    width: 60px;
    border-radius: 0;
  }
  
  .leftTitle {
    display: none;
  }
  
  .leftTop {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    top: 40px;
    font-size: 0; /* 隐藏文字，仅保留加号 */
  }
  
  .leftTop .iconPlus::before {
    font-size: 18px;
  }
}
